Pencil



Feb. 16,' 1954 H.l l.. LARSN PENCIL Filed Dec. 27, 1949" JNVENTOR. y L. Larsen Patented Feb. 16,1954

UNITED STATES vPrrrENT oEFicE PENCIL Harry L. Larsen, San Diego, Calif., assigner to Consolidated Vultee Aircraft'Corporation, San Diego, Calif., a. corporation of Delaware Application December 27, 1949, Serial No. 135,247

departments to produce the 'desired parts in their required dimensions. To construct the patterns or templates it is necessary to prepare full scale drawings of the parts of which they are the counterparts. A full scale drawing may be laid off with pencil directly upon a sheet of metal which has been sprayed with a white lacquer, or the delineation ofthe part may be placed on drawing paper or cloth; after the drawing has been made it is then reproduced, in a well known manner, on a metal sheet by a photographic process. The sheet of metal carrying the reproduced drawing is then cut along the lines appearing thereon to effect the template.

The greater the accuracy of dimension required in a template the more uniform must be the width of the lines of the drawing. To secure lines of uniform width the draftsman provides his lead with a chisel point and devotes a great deal of attention to maintaining the point to the desired size. Since it is usual to have lines appearing on the drawing that are'several feet in length the draftsmans skill is taxed to attain a result approaching the desired uniformity of width. Attainment of lines of uniform width is made still more diiiicult if the surface to which the drawing is being applied should have inequalities therein or be of a roughened character since abrasion of the point occurs more rapidly and a widened or irregular line results. Particular diiculty is experienced when working on a drawing cloth made of glass fibers because its texture is very rough. However, glass cloth is a desirable drawing material because it is dimensionally stable. The disadvantage of using glass cloth is that the draftsman must constantly be sharpening the lead to effect the desired point and even then abrasion occurs so rapidly that uniformity of line Width is not obtainable.

The principal object of the invention, is therefore, to provide a novel and improved lead hold'- ing device with which lines of uniform width are secured and which does not require the lead to be sharpened.

Another object of the invention resides in providing an improved form of marking device 6 Claims. (Cl. 1Z0-21) adapted to support a marking element which is of the same width as the width of the line to be drawn.

Another object of the invention lies in the pro Y vision of a holding device of novel construction for supporting a marking element of rectangular shape.

-A further object of the invention is the prolvision of a marking device embodying improved Ameans for gripping and supporting lead so that it is less liable to break.

'A still further object of the invention is to provide a marking device which is of simple and economical construction and which is effective and efficient in operation.

Other objects and features of the present invention will be readily apparent to those skilled inthe art from'the followingspecication and appended drawings wherein is illustrated a preferred form of the invention, and in which:

Figure 1 is an elevational view of a pencil embodying the present invention.

Figure 2 is an elevational view illustrating the lead gripping means.

Figure 3 is an enlarged, longitudinal sectional view through the pencil.

Figure 4 is a transverse section taken along the line IV--IV of Figure 3.

' Figure 5 is a transverse section taken along the line V-V of Figure 3.

' Figure 6 is a detail sectional view showing the chuck end of the barrel of the pencil; and e Figure 7 is a detail showing the forward end of the pencil.

.Having reference now in detail to the drawings there is illustrated a pencil constructed in accordance with the present invention and illustrated generally by the numeral IB. Pencil Ill comprises a barrel or casing II having an axial cylindrical bore I2 opening through the bottom I3 of the barrel and extending longitudinally to a recess M formed in the upper end I5 of barrel II. Recess I4 is of larger diameter than bore I3 and is provided with an internal thread I6.

The lower end of barrel II is cut to form a projecting'stem I1 of reduced diameter having an externally threaded portion I8, which threaded portion I8 terminates adjacent an annular shoulder 2| provided on barrel II. Stem I1 is provided with a plurality of longitudinally extending slots 22 which split stem I1 into four prongs or annularly arranged clamping fingers 23 which cooperate to eiect a four-jawed collet chuck. Barrel II is made of steel whereby iin-e.

gers 23 will have resiliency so that they Kcan be 3 iiexed or moved toward one another on the application of a compression torce to their exterior arcuate wall surfaces 24. It is understood that the material used in making barrel li and stem i1 is not limited to steel, though that is preferred, and it is contemplated that any metal or other material having resilient characteristics may be employed. A sleeve or nose-piece 25 having an internally threaded portion 26 and a frusto-conical or tapered portion 21 is tted over stem I1 to eiect a threaded engagement between sleeve. 25 and stem l1. The interior Wall surfaces 28 of the rusto-conical portion 2'l of sleeve 25 are tapered and are adapted to engage thefour resilient fingers 23 to apply a compressive. force, thereto to move them toward the longitudinal axis of barrel H as the sleeve 25is threaded onto portion i3 of stem i1. Theupper end of sleeve 25 is reduced to provide an annular pro-4 jection 3l which is adapted to extend into an .annular groove 32 -formed in shoulderfzyl on bar.-

.or socketfS'l which coaxially aligns with bore `l2 in barrel Il. Insertedinto the-socket 3l, are the .upperends of ya pair oielongatedleg,members l38 Aand .39.whichE-are substantially. half-round in transverse-section, and whichpass through bore `I2 and a coaxially alignedbore 4l.in sleeve 25 to proiectbelow sleeve .25.` .'IQhe projecting for- .wardrends 42 of members f3.3;and 33 areyprovided with an inward taper-as fshown. The. elongated members 3:8 .and-38 areiirmly. aixed to cap 35; this mounting is accomplished- .by'thelinclusion Abetween the gripping membersi andes .of a

shim or spacer 43 so that .insertion `of, tgheassembl-y into socket 3l eiectsaforcelt.

The head of the cap 35sucrose-slottedasshoyvn .aty 44, and will-accept.theendfof anappropriate screw driver whereby cap :3.5 j-canbe..madegto,it

,tightlyinto recess IA. `@Itis;understand that'cap 35 and--elongatedleg members ..3ii aand-.Sbcuid 'beintegral and formed out :oa Sinele ;,peue of stock, which stock after the Iormingioperatien would be kout. to effectspacedfleg members, -segmental in transverse section. `However to effect Aan integral. construction-l results in ai morenexpen.-

sive device and therefore. thefeonstruction shown in thedrawings s tobe preferred.

The substantially half-roundV -or vseg-mental Vgripping members 38 and` 39 vareslig-htly sprung so that .the freeportions of thegripping members :which extend beyond cap 35 diverge outwardly, as shown in Figure 2z to `be spaced apart. .With .the grippingmembers 38. and y39. 'thus-:normally biased to movev away; from one. another it;zis;easer .to Yinsert :a lead betweenthem.

vIn assembling the-pencil thelegsorygripping Amembers 3 8. and 39, are inserted; through :the .top of barrel H andxtted` into .bore :1.2. Cap 3;5 `is-then threaded into recess 14 to.,proa`ect the .forward ends 42 of leg members-38f-andz39-,be- .yond the lower/end of ther-barrel H. Since leg members 38 A and ...39.` arey biased,- as stated above, .to lie.. normally inspaced; apart relation, la lead 34 may be readily inserted at the opening at the lower end and upwardly into the space be- .tween members 33 and 39. The sleeve 25 is then threaded onto the stem I1 to force the interior tapered wall surfaces 23 thereof upon the exterior walls of clamping :lingers 23. Thus pressure moves the fingers 23 radially inwardly into engagementwith the leg rnembers and 39 to press the latter together'and ce'iuse them to tightly grip lead 34 and securely ho'ld it in posi- .tion for use.

When the lead 34 has been worn down and additional writing surface is required the sleeve .2.5 is ,backedpffgadistance sufficient to relieve thegpressureonclamping fingers 23 and release r'the-gripvofl legmembers 38 and 39 on lead 34. .The `lead 3.4could then be forced outwardly by shaking the pencil I3. However, a more efficient means for withdrawing the lead 34 from barrel Il is aorded by providing a pair of opposed .notches 45, asbestshown in Ei'gure 1. aty the projecting forwardendsfliZr, of the leg members .-38 land. 39, the notches extending inwardly from the longitudinal edges of. the leg mernlzaers,r @brand 3 9. With noteheseprovided,es ShQWIl. access .may be hadto.theverticalgedges of yleadfili,.permitting the application oflateralpressuretheref against. Lead 34, can then be moveddownwardly vby the draftsmans fingers to:` project thedesired .amount beyond theforwarmend of leg members 33 and 39. Sleeve25 is Ythen-again. movedaup- .wardly on steml'! to cause leg'membersigand .39 tightly to grip lead34.

Lead 34 which is supported by pencil -!-,Q .isr e, quired to be rectangular in crossrseetion, This rectangular lead willfbe heldby pencildil against movement either lengthwise orlaterally. This constraint of leadlii is secured by the cooperation of sleeve 25, clamping fingers 23,andlgrippingleg members .38 and 33. .Leg-members and .13e being of segmentalformhaye flatbase surfaces 5| which arepresented-.at the opposite iietyedes 52 of lead .34.and are adaptedtotightlyengage therewith under the pressure4 developedX by;.sleeve .25. This prevents lead A3,4* Vmoving endwiseont ,from betweendegmembersfiid and 353. Edgewise movement of lead ,34 is;y precluded by the .interior arcuate V,wall surfaces,- 53 .of the ,clamping fingers ,23. Figure 5 illustrates the relativeposition i si clampngngers 231 and leg.y members 93,8 an V.when the lead-34 .is ngrippedcondition, fltris noted that. the-wall surfaces -5,. 3o,f opposedfingers 23a andA 3D1-ie across andplose thespace between legv members :33; and ftffsdthat the portionsoi the .lateral edges of V,the lead. 34. zadjacent Welisa ,are confined. Injitting the Vupper,ends offleg `members 38. and 3el intoseeket .3;1; off-cup. care is taken. torso arrange the legfmembersthat w Men cap is'securedin recessj Moi-barrel? tithe position ofthe longitudinal edges. Qi thel-eezmembers .378and 3,3vvill bessuch. as tn permit themto be .of .two .opposed clamping rigersizr, arrangement of; lrparts vris' regni-red `wher .space .between-the, base surtacesgi ofV le su, I3-3vwill open-.ontogtheinteriorfwallsn aees;5 an .Opposedt pair of; damning tegels-.2 and l ri .Itis a relativelstsimple 'manufactu .toproperlylooatetheuppenends o members. .38.1 .and-f3 9 -within: soeketg v'h of reap J3 5` ,to .insure that .thez-space between fthesel legs,w.il1, when the cap 35 is secured, be obstr? teaggh `Sid? by gaf-vertien- Ofitee feall-Surfee wteeh @time ons@Sgtlampineneess- :Itis obtiens that the longitudinal edges of the leg members 38 andv39 are not restricted to the position shown in Figure wherein a prolongation of the planes of base 5I substantially bisect arcuate walls 53 of opposed iingers- 23a and 23h. The longitudinal edges can assume any position relative tothe arcuatewalls so long as a portion of these wall surfaces remains to extend across the entrance to thev space. What is to be avoided is a construction wherein the space between bases 5| of legs 38 and 39 valigns with slots 22 when cap 35 is iitted intozposition. i

The pencil construction hereinabove described is, particularly adapted for use with at leads whichv will have a thickness which is equal to the .desired width of the line to be drawn. The particular thickness employed is dependent on the character of the job, whether it is to be used by a draftsman on a lofting operation or by a carpenter on a wood structure. In lofting practice lines having a thickness of between .015 to .020 inch are particularly satisfactory. The present pencil is capable of supporting leads of the extreme thinness mentioned without their breaking or snapping. Because the thickness of the lead employed in the pencil is equivalent to the width required for the line to be drawn it is obvious that the operation of sharpening of lead is obviated. As a line is drawn the lead abrades without any gaining in thickness, since there can be no gaining. With the thickness of the lead remaining constant as the lead wears away the width of the line drawn by the lead will be uniform. v- The width of the lead employed must be only of an amount that will permit the lead'readily to ride over declivities and indentations in the surface being drawn ron. The width of the lead should be held toa small dimension in order that the size of the pencil might not become too great as to render it clumsy and unwieldy. vIn lofting practice a width of 0.10 has been found satisfactory for leads of the thinness above stated. The length of lead that could be accommodated is dependent on the length of the pencil. l

The hardness of the lead used is dependent'on the work being done and the roughness of the surface to which the drawing is being applied. A fairly hard lead, such as 6H, is preferred for lofting work on ber glass drawing cloth since it provides, without the exertion of great pressure, a

clean, sharp, black line which reproduces well when photographed. It is a matter of experience to select the proper hardness and avoid a too hard lead which is too brittle for the work to be done, or a too soft lead which will smear easily.

It is noted that portions of the exterior surfaces of the barrel Il and the sleeve 25 are knurled as indicated at and 5S for ease in removing and attaching the sleeve 25.

The construction herein described is characterized by its simplicity and by its eiciency. The employment of leg members 38 and 39 of segmental shape and the proper positioning of these members relative to the clamping ngers 23 affords a very efficient means for rmly and securely holding lead in operative position.

While certain preferred embodiments of the invention have been specically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

' Iclai'm: 1

1. In a pencil having a barrel with a bore opening to the exterior at each end thereof, means for supporting thin lead of rectangular section and of a thicknessv no greater than the width of a line to be drawn, said means comprising a pair of elongated gripping members of segmental section disposed in said bore, having their upper ends positioned adjacent the opening at the upper end of said barrel and xedly held against movement, their lower ends projecting to the exterior through the opening at the lower end of the barrel, and their fiat surfaces in opposition, a plurality of movable clamping elements provided upon said barrel disposed in surrounding rela'- tion to said elongated gripping membersy adjacent their lower ends, with a pair of said clamping elements arranged for engagement with the longitudinal edges of said elongated gripping members, and means operative on said clamping elements to move them into clamped position upon said elongated gripping members to apply a holding pressure upon a rectangularly shaped `lead disposed between the iiat surfaces of said elongated gripping members to restrain said lead against endwise and edgewise movements.

2. In a pencil having a barrel with a bore open-l ing to the exterior at each end thereof, means for supporting thin lead of rectangular section and of a thickness no greater than the width of a line to be drawn, said means comprising a pair of elongated resilient supporting members of segmental section disposed in said bore, having their upper ends positioned adjacent the opening at the upper end of said barrel and xed- 1y held against movement, their lower ends projecting to the exterior through the opening at the lower end of the barrel, and their at sur` faces in opposition, the free portions of said elongated resilient supporting members being biased for movement away from one another, a plurality of movable clamping elements provided upon said barrel and annularly disposed about said elongated supporting members adjacent their lower ends, with a pair of said clamping elements arranged for engagement with the longitudinal edges of said elongated supporting members, and means operative on said clamping elements to move them into clamped position upon said elongated supporting members to apply a holding pressure upon a rectangularly shaped lead disposed 'between the flat surfaces of said elongated supporting members to restrain said lead against endwise and edgewise movements.

3. In a pencil having a, cylindrical barrel with an axial opening therethrough, means for supporting thin lead of rectangular section and of a thickness no greater than the width of a line to be drawn,said means comprising a pai1` of elongated resilient supporting members of segmental section disposed in said axial opening, means, having a threaded engagement with the upper end of said barrel, for xedly holding the upper ends of said supporting members against movement and for positioning them with their iiat surfaces opposed, the free portions of said elongated resilient supporting members being biased for movement away from one another and the lower ends thereof projecting to the eX- terior of the barrel, a plurality of movable clamping elements formed integral with said barrel annularly disposed about said elongated supporting members adjacent their lower ends, with a pair of said clamping elements arranged for engagement with the longitudinal edges of said elon- 'gated supporting members, and a sleeve threaded on-'Ifttiei'lowerrend of: said barrel 'to embrace said elampingbele'mentsiandi to move #themv into clamping position 'upon said lelongated :supporting members-'tor'applya holding pressure yupon a reetang-i'iilarlyishaped lead' disposed` between, theilat surfaces'of fsaid i elongatedwsupporting members.`

1.4'.. -Irr'a pencil yhaving a' barrel-withfa .bore open-v ing :1 to-:thaexteriorrat each end thereof, me ans for upporting thin leadof: rectangular: section eddiereva-thicknessinergreater i than; the vWidm-I of alline to :.befdra-Wn, fsai'd means comprising a pair-tiff` elongatedi gripping members disposedv in sai'dboreiihavingetheiriupper; ends4 supported'fadj'acenttthe-opening at thevupper end of thebarrel and theirroppositeends; projecting to the exterior toJextend-below said barrel, each of said elongatedilgrippinglmembers. having a flat'surface,l theeelongate'drgripping members being arranged lin;theilczoreto positionfsaid flat surfaces-opposite each other, 'means operable on said elongated gripping members fori-applying a force thereon torrestrain,Z a lead of. rectangular shape disposed betweenrsaid flat surfaces against-endwise and edgewise movements, said lastl mentioned means comprising iiexible fingers arranged. to engage tkredongitndinal'.A edges` off-'said elongated gripping membersfanda a Imovable, means carried by said barrel forwapplying, -lpressure on :said-1 exible fingers, #said projecting Afends yof said. 'elongated gripping` members having notches .provided I at their: 'longitnfdinalredgesf.y to 1 afiordy access to the lead-z located lbetvveen the gripping members wherebysthelead-sean beagrasped-:andv movedendwisemitwardlysof Ifthe barrel.

51; Erraapeneil havingaebarrelwitha bore open-V ing @to i the;e exterior` at; each lenda thereof, a ,lead supportingrmenrbermounted' in said bore` for holding: lthin rectangular-'shaped lead epi-a thickness-ino-igreater'thansthe-widthof'ia line to be drawn.r 'comprising i -a pair of elongated s gripping mem'rzieis'zs off segmental: section disposed in. said bore;l supported' ati one of their yends vadjacentfthe opening :ati thefiupper end of the rbarrel andfhaving theirnppositefends; projecting youtofsaid bore toflextendfybelow said barrel, eachfroffsaid 'elongate .zgrippingfmembers havingv a "flat surface, trieselnnga-tedz; gripping members. being-1 arranged imthebore.toiposition said' flat surfacesinfopposition, -a plurality of "movable, clamping i ele,- mentstprdvided upon .said barrel -f disposed 1 an-` nularly, :biout saidlelongated gripping'mem-bers spacedurom their levveriv ends,y means carriedfby said barrel operative fon :said clamping f members tozi move 'i them; i, iirtely clamped? position upon. said elngatedggrippingg-members toa applyaholding pressure-upon a reetangnlarly shaped: lead disposed; between'theiat surfaceseoisaid elongated gripping timemfbers, v' said projecting ends l off: said elongatedigrippinggmembers havingenotches; pro- 3 vided; atfztheirzlongitudinaleedgesi toianordiaceess to the Y. leadv `located .zbetvveenthef :gripping vsi'mem berswhereby theileadfcanbe graspedfand moved endwiseioutwardlysofitheibarrel.

yIirtapencil'.' having a' barrel 1with 1af3eore3opening tothe exterior atfftheupper endoftthezbarrl, means. for @supporting .thin lead :of i'. rectangular section'sand of fa K thickness/'no greater "i than the width off: a. linea-.tobeidrawnrsadi meansifcomprisnf'gfam airiof elongated resilientzsupportingimefmbers yofi segmentalfsection disposed iiniisaidigbore. having their upper ends positioned addacentfthe upper openingemzsaid .barreliaridtheirzopposite endet. projecting to' .the ferterior ftof extend'ilzie'low said barrel, means, :having-.sa ithreaded".'engage ment with the uppereendf. oiisaid: barreLiiflxedly supp ortingthe .upperrf' ends ofrsaid iielongatedfresilient vi supporting members, thev reeflportions-:f said elongatedzresilient supporting membersibe ingrbiased-.for movement awayfromfone?another, each oflsaid elongated supportingamembershav inga-.ilatJ-surfaeeLtheelongated:supportingmemf bers'.=being f arranged Sin the :bore a to '.-positioni said flatsurfaces inioppositiona pluralitylof movable clamping elements provided upon said barrell'lannularly `disposed about-andfadjacent .the-slower endsy iof ksaid 'elongatef: supporti-ngA members, i with arpair of'saidclam-pingielements. arranged for engagement withthe, longitndmal :ledges-1 ofi said elongated supporting. Amembers,V #sleevev 'l1-means movably irionnted :onLsa/i'df barrel, embraeingzsaid clamping'. elements and operative thereentoimove 'them kinto oiampingfiposition upon saidelongated supporting members to apply?afvholdingpressure upon a rectangularly-:fshaped ylead di'sposedibetween the dat surfaces izofrsaid elongated :supparting f members, 'said projecting wendsitoff said elongated supporting members shaving :notches provided'at their longitudinal edgesto'saffordfaccesg. to the.y leadzdispose'dbetween the ielongated supporting members Wherebyzthetleadnzeam be grasped Aand moved fendwise r: outwardlyfzof tithe barrel;

:HARRY L.:

Y Reterenoes Cited nf .thea filet-of zthisx luttentt UNlTEDflST-AETES PATENTS Number Name 'Df 549,137` "Kiretelijian- Nov. T5, 1895 1,109,227 Hollenbergert, ----i Septjl, :1914 I 1,l44,069k ASchleicher J11ne222,l915 l,336,8l9 `Cook ,Apxt .13,1920 l 1,361,554 Terrell. .Deci.f'7, 1920 1,536,365 'Da Parmav Main-17, 1925 1,766,271 `rIurner i J une 24,.. 19130 FOREXGNATENTS.

Number Country Date' 19",*5i9 'Great Britain 1901 

